6 tablespoons unsalted butter, divided
1 cup finely chopped onion
10 eggs, divided
1 1/2 teaspoons salt, divided
3/4 teaspoon pepper, divided
1 (20-oz.) pkg. refrigerated hash brown potatoes
1 1/2 tablespoons chopped fresh tarragon
1 1/2 tablespoons sliced fresh chives
1/2 cup mascarpone cheese, softened*
1. Place oven rack in lowest rack position. Heat oven to 400ºF. Spray 12 muffin cups generously with cooking spray. Melt 4 tablespoons of the butter in medium skillet over medium heat. Cook onion 3 minutes or just until it begins to soften, stirring occasionally.
2. Meanwhile, whisk 2 of the eggs, 1 teaspoon of the salt and 1/2 teaspoon of the pepper in large bowl until blended. Stir in hash browns until coated. Stir in onion mixture. Spoon into muffin cups (cups will be full). With back of spoon, press into bottom and up sides, making an indentation in center. (Keep hash browns from spilling over edges to avoid overbrowning.)
3. Bake on bottom oven rack 40 to 45 minutes or until potatoes are tender and sides are brown. Remove from oven; run thin metal spatula around outside edges to loosen. Cool in pan on wire rack 5 minutes. Carefully remove potato baskets from pan; place on foil-lined baking sheet. (Potato baskets can be made 4 hours ahead.)
4. Place oven rack in middle position; reduce oven temperature to 300ºF. Whisk remaining 8 eggs, 1/2 teaspoon salt, 1/4 teaspoon pepper, tarragon and chives in large bowl 45 seconds or until frothy and blended.
5. Melt remaining 2 tablespoons butter in large nonstick skillet over medium heat. Pour in eggs; reduce heat to medium-low. Cook slowly 2 to 3 minutes or until eggs just begin to form curds, stirring constantly with heat-resistant spatula. Stir in cheese. Cook 1 to 2 minutes or until curds form but eggs are still very creamy. Spoon eggs into potato baskets.
6. Immediately bake potato baskets at 300ºF. for 5 minutes or until hot.
TIP *Mascarpone cheese is a double- or triple-cream cheese from Italy. Look for it in the dairy section of the supermarket or in Italian markets. If unavailable, substitute an equal amount of cream cheese.
PER SERVING: 440 calories, 27.5 g total fat (14.5 g saturated fat), 18.5 g protein, 30.5 g carbohydrate, 405 mg cholesterol, 855 mg sodium, 3 g fiber